Organized by the municipal health bureau, the drill will involve several government bureaus, including environmental protection, the center for disease control and fire brigade, said Shan Qingsheng, an official with the government's emergency response office.

The drill would focus on a scenario in which a "dirty bomb" loaded with explosives and radioactive substances is set off outside an "Olympic stadium", said Shan.

The bureaus involved would have to immediately react to the bomb. Using radiation detectors, the fire brigade would first find a safe route into the scene of the "bombing" before rescuers could enter to give first aid.

Medical teams would then give a radiation rating and define the type of radiation so that the injured could receive appropriate treatment.

The national medical base of nuclear and radiation incident, located in the Third Hospital of Peking University, will receive and treat "victims" of the drill, according to the drill plan.

Zhang Shulan, vice-director of the clinic department of the base, confirmed that the hospital is preparing for the drill.

A quick-response team, involving 63 medical workers, have been established, Zhang said.

"If Beijing is now hit by a 'dirty bomb', we are able to provide more than 100 beds for the injured," Zhang said.

But the organizers declined to give the exact time and location of the drill, nor how many people would be involved.